<em>Chastity Is for Lovers: Single, Happy, and (Still) a Virgin</em> by Arleen Spenceley. It would have saved me from so much pre-teen and teenage angst.
>I'm a convert, and I've come to realize that the way I learned modesty is pretty much entirely lacking.
This comment lead me to think of a book I recently read. I never realized before how much of a view we place in the Church on "purity". From what you're describing, I bet your background gave you a terrible view of not just modesty, but human sexuality in general.
I think your view of modesty would be very helped by a proper understanding of chastity - not as a "no" but as a wholehearted embrace of a good that God created in us. This book might help unravel some of the misconceptions you have and open you up to the freedom that the Church really seeks to offer.
"Chastity is for lovers," and a self-understanding of modesty is integral to living a chaste life.
http://www.amazon.com/Chastity-Is-Lovers-Single-Virgin/dp/1594714800
Edit - I have no idea what your current vocational state it, but don't let the title fool you. I would recommended this to anyone - Single, Married, Vowed Celibate